XCF_CR_STR_SCM_UTILIZATION

Description:

Provide a dynamic severity check exception when a structure exceeds one of the specified storage-class memory (SCM) utilization thresholds. The check informs an installation when structure assigned SCM has reached certain usage thresholds. The assigned SCM may become exhausted thereby becoming unable to provide continuous availability, additional structure capacity when needed during peak processing periods and provide relief when CF real storage allocated to the structure becomes constrained. The threshold percentages will be accepted as a check PARM.

Reason for check:

The percentage of SCM utilization for a structure should not approach an amount so high as to prevent the capability to provide relief for temporary CF real storage capacity or additional structure capacity when needed during peak processing.

z/OS® releases the check applies to:

z/OS V2R1 and later, or z/OS V1R13 with PTF for APAR OA40747 applied.

Parameters accepted:

PARM('[SCM_NONE(scm_none)]
     [,SCM_LOW(scm_low)]
     [,SCM_MED(scm_med)]
     [,SCM_HIGH(scm_high)]')

At least one threshold parameter is required to indicate a threshold percentage that the structure storage-class memory utilization should not exceed. The number must be between 0 and 100 inclusive. This check supports dynamic severity setting and threshold keywords to correspond with the severity levels. The severity of the exception is based on the provided corresponding thresholds.

Note:

When using dynamic severity, you may specify thresholds for one or more of the parameters to identify different thresholds by severity level.
You do not need to specify thresholds for all of the parameters.

scm_none: The percentage of in-use SCM, relative to the amount of SCM eligible for use by the structure, that will trigger severity-none processing. The SCM_NONE keyword can be abbreviated SCM_N.
scm_low: The percentage of in-use SCM, relative to the amount of SCM eligible for use by the structure, that will trigger a low severity exceptions. The SCM_LOW keyword can be abbreviated SCM_L.
scm_med: The percentage of in-use SCM, relative to the amount of SCM eligible for use by the structure, that will trigger a medium-severity exception. The SCM_MED keyword can be abbreviated SCM_M.
scm_high: The percentage of in-use SCM, relative to the amount of SCM eligible for use by the structure, that will trigger a high-severity exception. The SCM_HIGH keyword can be abbreviated SCM_H.

Default: SCM_LOW(1%),SCM_MED(80%)

Note: When specifying percentages for parameter values, your number for the higher severity case is larger than the lower case, as shown in the following example:

PARM('SCM_HIGH(90%),SCM_MED(50%),SCM_LOW(20%)')

User override of IBM® values:

The following shows keywords you can use to override check values on either a POLICY statement in the HZSPRMxx parmlib member or on a MODIFY command. This statement may be copied and modified to override the check defaults:

UPDATE CHECK(IBMXCF,XCF_CF_STR_SCM_UTILIZATION)
SEVERITY(MED) INTERVAL(000:15) DATE(20120322)
PARM('SCM_LOW(1),SCM_MED(80)')
REASON('Structure assigned storage-class memory should be'
       'available for additional structure capacity'
       'when needed during peak processing.')            
VERBOSE(YES)

Reference:

For more information, see z/OS MVS Setting Up a Sysplex.

Messages:

This check issues the following exception messages:

IXCH0224I
IXCH0225E
IXCH0925I

See the IXCH messages in z/OS MVS System Messages, Vol 10 (IXC-IZP).

SECLABEL recommended for MLS users:

SYSLOW